/// @file misc.c
/// @brief 一些实用程序.
/// @author Zhang Hao, stavrosatic@gmail.com
/// @version R1.5
/// @date 2017-10-12
#include "misc.h"

GPIO_InitTypeDef    GPIO_InitStructure;
SPI_InitTypeDef     SPI_InitStructure;
DMA_InitTypeDef     DMA_InitStructure;
NVIC_InitTypeDef    NVIC_InitStructure;
USART_InitTypeDef   USART_InitStructure;
EXTI_InitTypeDef    EXTI_InitStructure;

const uint8_t __attribute__ ((section("FLASH"))) ByteReverseTable[256] = {
    0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0, 0x10, 0x90, 0x50, 0xd0,
    0x30, 0xb0, 0x70, 0xf0, 0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
    0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8, 0x04, 0x84, 0x44, 0xc4,
    0x24, 0xa4, 0x64, 0xe4, 0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
    0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec, 0x1c, 0x9c, 0x5c, 0xdc,
    0x3c, 0xbc, 0x7c, 0xfc, 0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2,
    0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2, 0x0a, 0x8a, 0x4a, 0xca,
    0x2a, 0xaa, 0x6a, 0xea, 0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
    0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6, 0x16, 0x96, 0x56, 0xd6,
    0x36, 0xb6, 0x76, 0xf6, 0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee,
    0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe, 0x01, 0x81, 0x41, 0xc1,
    0x21, 0xa1, 0x61, 0xe1, 0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
    0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9, 0x19, 0x99, 0x59, 0xd9,
    0x39, 0xb9, 0x79, 0xf9, 0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5,
    0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5, 0x0d, 0x8d, 0x4d, 0xcd,
    0x2d, 0xad, 0x6d, 0xed, 0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
    0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3, 0x13, 0x93, 0x53, 0xd3,
    0x33, 0xb3, 0x73, 0xf3, 0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb,
    0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb, 0x07, 0x87, 0x47, 0xc7,
    0x27, 0xa7, 0x67, 0xe7, 0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
    0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef, 0x1f, 0x9f, 0x5f, 0xdf,
    0x3f, 0xbf, 0x7f, 0xff
};

vu32 g_nms;

/// @brief 微秒级延迟. 
/// @param n 要延迟的微秒数.
/// @retval None
void _delay_us(vu32 n)
{
    n *= 5;
    while (n--) ;
}

/// @brief 毫秒级延迟, 循环实现, 精度较差, 但可在中断服务程序中使用. 
/// @param n 要延迟的毫秒数.
/// @retval None
void _delay_ms_loop(vu32 n)
{
    while (n--) {
        _delay_us(1000);
    }
}

/// @brief 毫秒级延迟, 用SysTick中断实现, 精度较好, 不能在中断服务程序中使用.
/// @param nms 要延迟的毫秒数.
/// @retval None
void _delay_ms_systick(vu32 nms)
{
    g_nms = nms;
    while (g_nms > 0) ;
}

/// @brief 用于毫秒级延迟的计数器, 由SysTick中断服务程序调用. 
/// @param None
/// @retval None
void _delay_nms_mm(void)
{
    if (g_nms > 0)
        g_nms--;
}

/// @brief 8位字节逆序, 查表实现. 
/// @param c 要逆序的字节.
/// @retval 逆序后的字节.
u8 ByteReverse(u8 c)
{ 
    return ByteReverseTable[c];
}
